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Old 08-16-2007, 05:53 PM
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David Powell David Powell is offline
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Ken, the only direct comparison I can make is to my K&K bassmax. Using the Acoustic Image Coda Combo (down-firing 10, forward 5 and tweeter), I can run the K&K at 12:00 o'clock on both the master and the channel gain with no danger of feedback in most situations. I've been able to use the DPA mic alone in a couple of situations where I have previously used the K&K alone, so direct comparison in those rooms is possible. In those rooms I was able to use the DPA with the channel gain at the 9:00 o'clock position with the master at 12:00 o'clock, so the gain is considerably reduced. Of course the "loudness" that is produced is not necessarily the same relation as the channel gain, but it is a pretty good indicator.

To compensate, I used my Ampeg PB 212H cab as an extension on the AI. This increases the efficiency of the head (400W to 500W) and more than doubles the speaker area, so it makes up the difference quite well. I'm not sure why, but adding the extension cab did not decrease the channel gain before feedback. I placed that cab about 90 degrees to my DB off to my right and just slightly forward. The AI was behind me and slightly left. These were pretty close quarters. I did use the notch filter on the AI with the DPA mic. Position of the notch is definitely room dependent. With a concrete floor the notch is at the top of the high frequency range while on a carpeted hollow wooden stage, it was rolled all the way to the bottom end. Also in one room it was better with the bass boosted just slightly on the amp. The other room was OK with flat EQ (the wooden stage).

This approach works really well in a small room and of course sounds much better than the K&K. I was actually very surprised at how good the feedback rejection is on the DPA. It's definitely the best of any cardioid condenser I've tried for anything. It rivals some dynamic CAD vocal mics I have that are as near to feedback proof as any mics I've seen. Unfortunately I haven't tried any of the other miniature condensers.

It seems if it is going to feed back, the position is not too important except if the AI is 45 degrees and in back of the bass. In front, 90 degrees to the side or even directly behind the bass is fine. I was able to move around just as I normally would and didn't feel like a slight side step would set the thing howling, but there is a fine edge to the level, and I have to stay under it. Just a tick beyond that 9:00 o'clock position and all is lost. First it gets that really boomy uncontrollable response and just beyond that, it howls at whatever mid frequency the room supports.

One day we'll have to gather up a bunch of these other mics and test them side by side. I don't know many other players using mics locally. Chris Wood is from here and I see his brother Oliver pretty regularly and we are good friends and I know Chris uses a tiny mic mixed with a Fishman FC. I think it must be the Crown mic that is sometimes supplied with those. He has it mounted in a similar position to what Bob B. describes. On stage he is playing mostly with the Full Circle cranked up. Maybe next time I see those fellows I can egg him into a comparison some way. He's a bit famous you know, but pretty down to earth.

I really do like the fact that the DPA mic as you see it is all there is to it;- no pre-amp or battery box to connect in between. Of course it means you must have a phantom powered system but these days that is almost every house board.
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